Bristol Myers Squibb announced positive interim results from its Phase 3 EXCALIBER-RRMM study, showing that iberdomide in combination with standard therapies demonstrated a statistically significant improvement in minimal residual disease (MRD) negativity rates compared to the control arm in patients with relapsed or refractory multiple myeloma (RRMM). The investigational cereblon E3 ligase modulator (CELMoD™) was combined with daratumumab and dexamethasone in the trial.
Novel Protein Degradation Approach Shows Promise
The study results represent a significant milestone for iberdomide, which Bristol Myers positions as the first of a novel class of medicines called CELMoDs. "Iberdomide represents the first of a novel class of medicines, called CELMoDs, which has the potential to create a new foundation for multiple myeloma treatment that may be combined with other therapies," said Anne Kerber, Senior Vice President, Head of Development, Hematology, Oncology and Cell Therapy.
The drug works through targeted protein degradation, tagging certain proteins essential for cell survival for destruction by the body's own regular disposal mechanisms. This approach builds on Bristol Myers' more than two decades of scientific expertise in protein degradation, making it the only company that has successfully developed and commercialized protein degrader agents.
Trial Design and Continued Evaluation
EXCALIBER-RRMM (NCT04975997) is a Phase 3, multicenter, two-stage, randomized, open-label study comparing iberdomide in combination with daratumumab and dexamethasone (IberDd) versus daratumumab, bortezomib, and dexamethasone (DVd) in RRMM patients. The study enrolled approximately 664 patients in Stage 2, with 1.0 mg iberdomide identified as the optimal dose in Stage 1.
Based on the Data Monitoring Committee's recommendation, the trial will continue without changes to evaluate the other dual-primary endpoint of progression-free survival (PFS), along with key secondary endpoints including overall survival and safety. The safety profile of iberdomide in combination with daratumumab and dexamethasone was generally consistent with previous studies.
Clinical Significance of MRD Negativity
Minimal residual disease refers to the small number of cancer cells that may remain in a patient's body after treatment and are undetectable using conventional diagnostic methods. Modern MRD detection methods, such as next-generation sequencing and next-generation flow cytometry, can identify one malignant cell among 100,000 to 1,000,000 normal cells.
MRD negativity has emerged as a highly sensitive and clinically meaningful tool for evaluating treatment response in multiple myeloma. While MRD negativity doesn't necessarily mean all cancer cells are eliminated, it may predict improved clinical outcomes, including longer remission and survival. MRD is increasingly being used in clinical trials as a surrogate endpoint for progression-free survival and is gaining recognition from regulatory authorities.
Regulatory Path and Commercial Potential
Bristol Myers plans to discuss these results with health authorities, though company executives have previously indicated that approval would probably only come if iberdomide meets its other objectives. "We would have to look at the totality of the data, that other endpoints are moving in the right direction, because the supportive evidence would be needed from a regulatory perspective," said Samit Hirawat, Bristol Myers' then-chief medical officer, during a July conference call.
The drug is positioned as a potential successor to Bristol Myers' blockbuster blood cancer drugs like Revlimid, which hit nearly $13 billion in sales at its peak in 2021, and Pomalyst, which recorded sales of $3.5 billion in 2024. Consensus estimates project iberdomide could generate around $1.3 billion in annual sales by 2035, with analysts noting substantial upside potential if the data prove promising across all endpoints.
